The overwhelming majority of all overseas cargo is presently transported by ship. As compared to the transport of overseas cargo via conventional high altitude, high-speed aircraft, overseas cargo transport via ship is often 4 to 5 times slower but less expensive by a factor of ten. As such, only about one percent of all overseas cargo is time sensitive enough to necessitate shipment via conventional air transport. Given the gaps in the cost and transit time between ships and conventional air transport, there is an apparent need in the art for an alternative transport vehicle that facilitates the relatively efficient, rapid and cost-effective overseas transport of cargo.
Large airships or blimps represent one alternative mode of overseas transportation. Large airships have a higher payload-to-drag ratio than conventional aircraft and as such, are more efficiently operated. However, considerations for the size of the hanger for housing the airship, the stresses on the airship structure, the maneuverability of the airship, the airship's relatively slow cruising speed and the dependence on weather conditions render airships impractical for reliable overseas cargo transport.
Another alternative to the conventional overseas cargo transport modes is the conventional ground-effect aircraft. Ground-effect operation occurs when an aircraft is flown in close proximity to the surface of the earth such that the downward motion of the air under the aircraft is constrained. The constraint of the air under the aircraft reduces induced drag and thereby increases the efficiency of the aircraft. Conventional ground effect aircraft, however, are not well suited for the overseas transport of a high volume of cargo. In this regard, no ground-effect aircraft is known to have a configuration which permits safe ground-effect operation over rough seas as a typical altitude for ground-effect flight is about 0.1 wingspan lengths or less. Accordingly, large swells could prevent operations or necessitate alternative routes which would tend to increase costs and disrupt delivery schedules.
Furthermore, when the known ground-effect aircraft are scaled up in size to accommodate high volume cargo transport, several problems are encountered. For those ground-effect aircraft that take off and land in water, the fuselage of the aircraft is configured to permit flotation while the aircraft is fully loaded. As such, the hull or fuselage of the aircraft necessarily has a large area for displacing a sufficient volume of water to permit floatation. The large area of the hull, however, increases both the weight of the aircraft and its parasite drag to thereby reduce the aircraft's capacity and operational efficiency. Similarly, scaling-up the design of a conventional ground-effect aircraft that is configured to take off and land on conventional land-based runways is also impractable. For example, the large wingspan that is required to permit the aircraft to efficiently transport a high volume of cargo and the magnitude of the load that is exerted by the landing gear onto the runway would significantly limit the number of runways from which the aircraft could be operated.
Accordingly, there remains a need in the art for a ground-effect aircraft that is configured to permit the relatively efficient, rapid and cost-effective overseas transport of cargo.